Notes: I usually use a piece of graph paper instead of drawing the lines. Just overlay it on the drawing. (Make sure the scale is in relation to the drawings, but even if it isn't, you can make relationships between waterlines with any scale graph paper)

Here is where I checked to see if my estimate would be way off on this sketch.. Most boats of this size are designed for about 500 pounds to bring it to the design waterline. (That's 2 each 160 pound people = 320 # and a 150 # +/- pound boat)